Featured Lotus Evija Aims to Be the World's Most Powerful Electric Car

Seems lovely overall, though I’m disappointed to hear that they settled for digital cameras for side view mirrors.

 

Before this, the thought that the next Tesla Roadster is a practical car never crossed my mind.

It's the future, man.
Depending on where the screens are mounted, it could mean the eyes spend more time looking forward while your going 200mph.

 

My concern is latency.

An analog video circuit can get you a picture of what used to be behind you in a few milliseconds- so it will still be within a foot or two of where your vision is telling you.

A very fast digital video system needs about 30ms end to end, so it’s capable of magnifying the error by about 10x.

F1 could probably improve their lap times with video mirrors, but they won’t do it. Granted they are dealing with higher speeds and nearer passes than even this exotic car.

 

When a car goes as fast as this one there is no need to look in the mirrors. No one is ever gaining on you. Maybe you'd use the mirrors/cameras when parking.

Mike

 

No, that is a typical video system when you don't care much about latency.
Somehow the best PC gamer machines are able to get over 100 frames per second and play games over the internet with lots of other players. I think it must be possible to get a video signal to travel a few inches and display it in 5 or 10 ms...if they need to.

Mike

 

That's an average "tv" type signal today. That number generally comes from the delay in 30fps devices. You need 1 frame of data to be received before you can apply it to the screen in full for display while you buffer the other frame. That 1 frame latency at 30fps is 33ms.

However, 30fps is super slow for these types of video systems. I have seen some awesome high speed sensors that can do 2.1mfps. That's million frames per second. Those won't be in the Prius anytime soon. But the technology exists. For a consumer vehicle, 240fps to 480fps are very cheap sensors today and would work just fine. 480fps sensors are cheap because they were developed for the 3D TV's that needed 2 frames of 240fps images, 1 per eye. The sensors are all contained within a digital chip with a core and are stupid simple and cheap. If you want faster than that, as far as I know there is no easy/cheap consumer version available today. But that's not historically been a problem for a $2m vehicle.

 

My 4 year old GoPro does 240 fps
You could also process the frames as slices (partial frames) and send a slice at a time

Mike

 

Almost full-circle - given that TESLA's original Roadster was heavily based on a LOTUS.

 

Wow, over 200mph to the next traffic jam. Most impressive.

 

What I’m getting at here is that you can do a low-latency analog CCTV system pretty easily.

You can also do a much higher latency digital HD CCTV system with off the shelf parts.

Now… getting the low latency of an analog system using digital video gear? That’s… tougher, to say the least. And if they really pulled it off, I want to see what they did.

Frame rate isn’t the same thing as live latency. A 240fps gopro is neat, shot plenty with them myself. I’ve also worked professionally with the Phantom line. But both have issues with latency, getting that first frame out to, and displayed on, a live viewfinder.

And again, Formula 1 could spend millions per car on mirror replacement… they have the budget. Yet they aren’t going for it. The drivers don’t want it; too much lag.

 

The next Tesla Roadster will likely hit 250mph.

There is also the human latency to consider. Shifting eyes, refocusing on a mirror, and then back takes time. The difference in placement means this takes less time for in a F1 car than one designed for the street.

Then there should be different driving behavior between the two. On a street car, the mirrors are for situational awareness of other cars. This doesn't require precise location data. For actual lane changes, drivers on the road should all be physically turning their head to look directly into their blind spots. Even if the helmets, and car design allowed such direct checking of to the side, the speeds F1 is traveling at is too high. The time taking eyes from looking forward is too high for safety.

In short, true racing car needs aren't the same as those for cars designed for the street.

 

I concur with you on this. What’s holding me up is where you'd draw the line for a high-performing car? Should it have race safety standards, or mere street ones? It’s always weird for limited run hypercars like this.

I concede that video vision is coming one way or another- it is my hope that some very rigid standards* are applied early enough in their introduction to matter in terms of universal familiarity and utility.

*specifically: image latency, minimum resolution, absolute contrast and luminance output as well as dynamic range and harmonization with other light-emitting cockpit displays and devices, composite display modes and failure mode handling.

And in the interests of moving the discussion along… I love the shape of this car. That asymmetric void contour on the hood is bold!

 

There is one on the other side. The first photo perception hides it well.

 

Good catch! I figured one of the images had been flipped, since that happens often enough. I see the contour. Well I guess it’s only a little less bold then.

 

2.1 Mill? Let me grab some loose change out of the sofa, I'll go buy one for me and one for the wife. What colors are available?